Electrolytic condenser and method of making the same



Dc l2, 1939. c. DE LANGE ET AL ELECTROLYTIC CONDENSER AND METHOD CF MAKING THE SAME Filed Feb. 28, 1938 Patented Dec. 12,f 1939 UNlTED .STATE-fsf PATENT OFI-ucl;

r:assos:

ELECTBOLYI'IC CONDENSED. AND METHOD QI' MAKING THE SAME Cornelis deLanseoand Adriaan Jan Juriaan lLam` beek, Eindhoven, Netherlands. assignors to N. V.

Philips' Gloeilalnpenfabrieken, Eindhoven,

therlands man remar, za, 193s-, sexismo. 193,110

In Germany March 5, 1937 ,roam loins-315) n monl container so asto be insulated from each The present invennon rentes-.weiectrolyue condensers in which apluralityoi electrodes are andto a plurality of electrodes in a single-container, amilV numerous constructions of` have been proposed. Such cnstructionaliowever, gener- A live Vto manutacture'are oi* relatively large size ,ally have the disadvantages that they are expenper unit capacity, and have a high series resist- It is of considerable importance'that theseries resistance-which depends upon-the length of the path ci the current ilowing from the current supply conductor through the electrolyte to the -dielectric i. e. the oxide nlm-bess short as possible. In many known electrolytic condensers the container consists oi' conductive material and isused as a supply conductor for the electrolyte, and the series redstance is consequently substantially determined by the speciilc .resistance ot the electrolyte. In such condensers particularly when they are used on comparativelyV high operating voltages, this resistancehas an appreciable valuel As the speciilc4 resistance ofan electrolyte at an operating voltage of 500 volts has a value 'of the order of magnitudeof *10,000

ohm. cm., it is evident that tokeep the series' resistance as low iisv possiblethe anode construction must be such that the path oi-the current flowing from the anode to the container m'ustbe asshortaspossible. y

On'e object'oi our invention is to overcome the above disadvantages and to produce 'a condenser oi the above type which is inexpensive to manufacture.'

4Another object is to reduce the size as well as the series resistance of such condensers. A further object is to p'oduce a condenser which can be readily mounted on a panelf A still further object is toprovide electrodes which can be manufactured by drawing or impact extrusion.

Still further objects and advantages .of the present invention will be apparent to thoseskilled in the art from the following particular description. g `In accordance with the invention,.we'produce a plurality oi electrodes from a single suh- `stantially the same size as Ithe internal 'dimensions oi the container, by dividing this body along planes parallel to its longitudinal The electrodes so formed are arranged within a c'oma bi-polar, elecother, and are provided with individual supply conducors.

Such a construction makes it `possible to arrange within a container of a given size, a plurality of condenser units each of which has the `highest possible capacity, while at the same time 'the series resistance is very low. Furthermore,

produced, for example, 'by means of the more or less complicated process of drawing or of impact extrusion.

According to a particular advantageous embodiment of 'the invention, the electrodes are y produced from a, body having a'bott'om portion the manufacture of thecondenser is greatly simpliiled because it'is possible to obtain a plurality of electrodes after only a. single body has been ever, ii only a single body is made by this method I and this body is axially divided, for example by sawing, into a plurality of electrodes, the cost is much less than if each electrode were produced individually by extrusion. As a res'ult the efliciency oi the device utilized for drawing or torrizioned electrodes is arranged. Thus, each electrode is surrounded on all sides by a wall which acts as a supply conductor for the electrolyte, and asaresult the currentpath and the series resistance are very small. .By makingl these par-- titions of a non-nlm forming metal we prevent the formation on their surfaces of an oxide layer which, because of its lhigh resistance, would again increase the series resistance. Furthermre, such an oxide layer is undesirable because it generally forms a dielectric layer,'with the result'that a second capacity, is connected in series with the capacity formed bythe electrode and the electrolyte, and unfavorably iniiuences the totalv capacity of the condenser. j

In order that the invention can be clearly understood and readily carrledinto eect, we shall describe the same more fully with reference to the accompanying drawing in which Figure 1 is a sectionized side-view of a condenser according to the invention,

Fig.v 2 is aperspective view of the body from which the anodes of Fig. 1 are formed,

Fig. Sis a perspective view of the partition of Fig. l, and

Fig. 4 is a plane view of a panel with the condenser of Fig. l mounted thereon.

The condenser shown in Fig. l comprises a cup-shaped metal container i, for instance of aluminum, whose upper end is formed with a proturbance I3 having two holes Il closed by a rubber band I5 which, in known manner, relieves the pressure developed within the container during operation. The lower end of the container is closed by 'a member 3 of suitable insulating material, such as Bakelite, and to eiect a liquid-tight joint, the edge 'of container I is spun at 2 over the edge of member 3 with the interposition of a gasket Iii, for instance of rubber.

Within container i are two electrodes d and having projecting portions 6 and i respectively, which extend through apertures in gasket iii and member The ends of portions E and i are riveted over with the interposition of suitable terminal lugs 8 and As shown in Fig. 2, the electrodes H and are produced from a single body 2d consisting of a .bottom portion 2t and a pluralityo concentric annular portions extending perpendicular thereto. Such a body may be readily produced by extrusion, the portions d and l' o' Fig. l being formed at the same time. Instead of dividing body 26 into two parts, it can of course be divided along planes passing through its axis into any desired number of parts.

As appears from Fig. l., electrodes 4 and 5 are spaced apart so as to be insulated from one another, and a partition l i of a non-ilming material which is not attached by the electrolyte, rsuch as ferro-chromium, stainless steel, or Chromed aluminium, extends between them. Partition I l and container i act as a current supply conductor for the electrolyte 3U, which is of a suitable type, and acts as the cathode of the two condenser units in which the formed electrodes 4 and 5 act as anodes. To increase the capacity of the condenser, the surface of anodes t and 5 may be etched, and to prevent corrosion thereof they are located below the level of theelectrolyte 30, which must be, for example, at A. As shown in Fig. 3, partition II is bent at right angles at I8, and in the middle of the bend a large aperture I 1 is provided which facilitates the escape of the gas produced during operation in the left half of the container through thepapertures Id.

During the manufacture of container I, which may also be effected by the so-called impact extrusion, two tips I2 are formed (only one ,being visible in Fig. 1). The electrical and mechanical connection of partition II to container I is effected by inserting tips I2 in apertures I8 provided in partition I I and by riveting over the ends of tips I2. As partition II is comparatively long .and thin, it is rather weak and may move in the space between the electrodes 4 and 5, andcome.

into contact with the latter.;` To prevent. such contact, rubber rings I 9 and!!! are provided at diierent points on partition II (see Fig..3)

It is evident that instead of a single iiat partition as shown, it is possible to use complex partitions which divideI the container into three or more compartments, 'the number of which depends on, the number of formed electrodes which are arranged on the bottom 3 and insulated from one another.

Fig. 4 illustrates, by way of example, one manner of mounting the condenser on a mounting plate ZI, which is provided with an aperture 22 through which the projecting part 3I of the mem ber 3 of Fig. l extends. The condenser is secured to plate 2l by a U-shaped strap 23, whose ends bear upon the plate and which is secured to' member 3 by a screw 2E which engages threads of a bore 25 in member 3. The aperture isnot exactly the shape of part 3i, but is given the shape shown to effect a saving on punchingtools, a special tool being superfluous. Only two normal circular punches are used in this case, via. one of smaller diameter for punching two apertures at left and at right and one of larger diameter for punching away the material between these two apertures.

It will be noted that construction of a container according to the invention is vvery compact which results. in a saving of space 'and makes such con densers Very suitable for many purposes, for example, lters for rectifiers which, as is weil` known, employ at least two condensers for smoothing the pulsatory direct current. If two individual electrolytic condensers are used, as is customary, these condensers each occupy a certain space on the frame plate on which the rectier and the lters are arranged. Besides, the mounting of these two condensers requires twice as much work. It will be clear without further explanation that the use of a single condenser according to the invention has an. appreciable advantage, as regards required space and time required for mounting.

While we have described our invention in connection with specific examples and applications we do not wish to be limited thereto, but desire the appended claims to' be construed as lroadly as permissible in View of the prior art.

What we claim is:

l. In the manufacture of electrolytic condensers having a plurality of electrodes arranged withina common container, the steps of extruding a body which matches the internal dimensions of the container, and dividing said body along planes parallel to its longitudinal axis to form the electrodes.

2. In the manufacture of electrolytic condensers having a plurality of electrodes arranged within a common container, the steps of forming a single body having a bottom portion and a plurality of concentric annular portions extending perpendicular to the bottomportion, and dividing said body along planes parallel'to the axis of said annular portionsto form said electrodes.

3. An electrolytic condenser comprising a common container, an electrolyte, a plurality of electrodes arranged in spaced relationship Within said container and insulated therefrom, each electrode being in the shape o'f a sector of a cylindrical body and having a base portion and a plurality of parallel extensions perpendicular to the base portion, and a supply conductor for each of said electrodes.

CORNELIS DE LANGE.

ADRIAAN JAN JURIAAN LAMB' EEK. 

